1. Heat oil in a large saucepan or pot. Cook lamb until browned, then set lamb aside on a plate.
2. In the same pan, cook onion, celery, capsicum and garlic. Stir for 3 minutes until onion softens.
3. Add lamb back into the pan, and 2 cups of beef stock. Bring to a boil, then reduce heat to a simmer and cover pan with the lid. Simmer for 15 minutes until meat is tender.
4. Add silver beet and lemon juice, season with black pepper. Simmer uncovered for 5 minutes or until silver beet wilts. Serve while hot.